NULL Pointer Dereference Affecting linux-qemu-melange package, versions <6.18.38-r0


Severity

Recommended
0.0
medium
0
10

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Threat Intelligence

EPSS
0.13% (3rd percentile)

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  • Snyk IDSNYK-CHAINGUARDLATEST-LINUXQEMUMELANGE-17949840
  • published11 Jul 2026
  • disclosed29 Jun 2026

Introduced: 29 Jun 2026

NewCVE-2026-53325  (opens in a new tab)
CWE-476  (opens in a new tab)

How to fix?

Upgrade Chainguard linux-qemu-melange to version 6.18.38-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream linux-qemu-melange package and not the linux-qemu-melange package as distributed by Chainguard. See How to fix? for Chainguard relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

agp/amd64: Fix broken error propagation in agp_amd64_probe()

A NULL pointer dereference was observed in the AMD64 AGP driver when running in a virtualized environment (e.g. qemu/kvm) without a physical AMD northbridge. The crash occurs in amd64_fetch_size() when attempting to dereference the pointer returned by node_to_amd_nb(0).

The root cause of this crash is broken error propagation in agp_amd64_probe(): When no AMD northbridges are found, cache_nbs() correctly returns -ENODEV. However, the probe function erroneously checks the return value against exactly -1, rather than < 0.

As a result, the hardware absence error is masked, allowing the driver to improperly proceed with initialization. It eventually calls agp_add_bridge(), which invokes amd64_fetch_size(). Since the hardware does not exist, node_to_amd_nb(0) returns NULL, leading to a General Protection Fault (GPF) when accessing its ->misc member.

Fix the issue by correcting the error check in agp_amd64_probe() to abort properly when cache_nbs() returns any negative error code. This prevents the driver from erroneously proceeding without hardware, thereby avoiding the subsequent NULL pointer dereference at its source.

CVSS Base Scores

version 3.1